BACKGROUND OF THE INVENTION
1. Field of the Invention
[0001] This invention relates broadly to a system for bone fracture fixation. More particularly,
this invention relates to an improved method and a related system for fixation of
fractures of relatively small bones.
2. State of the Art
[0002] Metacarpal fractures are very common. Immobilization of the metacarpal bone on either
side of the fracture is imperative for proper healing. However, the location of the
fracture presents several difficulties to ideal immobilization.
[0003] The most frequently used treatments for immobilizing the fracture are splinting and
casting. However, due to the location of the metacarpal bones, these treatments fail
to maintain proper fracture reduction in the metacarpal bones. Strong fixation is
possible with techniques using plates, fixation screws, and fixation pins attached
to the affected bones through operative treatment. While these types of fracture reduction
devices are commonly used in larger bone fractures, e.g., ulnar, tibial, or femoral
fractures, such operative treatment generally implies a formidable incision and exposure
of the fracture site. Therefore, these techniques are often judged to be too invasive
for the relatively small and fragile metacarpal bones.
[0004] An alternative less invasive technique has been used in which a small incision is
made in the skin proximal the metacarpal bone, a boring tool is inserted through the
incision and is used to drill a small hole into the metacarpal bone, the boring tool
is removed, and then the physician feeds the pin through the incision and into the
small unseen bore in the bone. However, feeding the pin through the skin is a blind
operation with no manner provided for indicating to the physician the relative location
of the pin and the small hole bored in the bone. As such, the technique is objectionable
to both physician and patient as blind feeding can result in exacerbating damage to
the surrounding tissue. In addition, the implanted pin fails to provide torsional
fixation for fractures which need to be rotationally immobilized.
[0005] Furthermore, similar problems exist with respect to metatarsal and phalangeal fractures.
It is therefore an object of the invention to provide a fracture fixation system which
permits stable fixation for metacarpal, metatarsal, and phalangeal fractures, and
fractures of similar bones.
[0006] It is another object of the invention to provide a fracture fixation system which
provides internal percutaneous fixation for metacarpal, metatarsal, and phalangeal
fractures, and fractures of similar bones.
[0007] It is also an object of the invention to provide a fracture fixation system which
provides torsional stabilization for metacarpal, metatarsal, and phalangeal fractures,
and fractures of similar bones.
[0008] It is a further object of the invention to provide a fracture fixation system which
provides a fixation system which is adjustable in size for metacarpal, metatarsal,
and phalangeal fractures, and fractures of similar bones.
[0009] It is an additional object of the invention to provide a fracture fixation system
which when compared to prior art operative treatment is relatively noninvasive.
[0010] In accord with these objects, which will be discussed in detail below, a fracture
fixation system is provided. For simplicity, the fracture fixation system generally
will be described with reference to the metacarpal bones, although it also applies
to metatarsal bones, phalangeal bones, similar bones. The system facilitates the insertion
of one or more fixation pins into the medullary canal of a fractured metacarpal bone
for stable bone fixation.
[0011] According to the present invention there is provided a fracture fixation system for
stabilizing a fracture of a human bone, said system comprising: a fixation pin having
a proximal end and a distal end, said fixation pin being sized to snugly fit within
the medullary canal of the bone and having a stiffness sufficient to immobilize the
fracture and a flexibility sufficient to permit the fixation pin to bend to facilitate
insertion into the medullary canal; and an elongate shaft having a proximal end, a
distal end with means for boring a hole in the bone in a first direction axial with
said shaft, an axial pathway and a pin guide comprising a distal laterally exiting
bore in said shaft adjacent said distal end of said shaft and communicating with said
axial pathway; said fixation pin and said shaft being adapted such that said fixation
pin is axially movable through said axial pathway and the laterally exiting bore for
guiding said fixation pin beyond said distal end of said shaft into the medullary
canal of the bone at an oblique angle relative to said first direction.
[0012] According to one embodiment of the invention, the system includes a fixation pin
and an instrument for implanting the fixation pin. According to a first embodiment
of the invention, the instrument includes a main handle and a pin handle movable relative
to the main handle. The main handle includes a proximal end, a distal end, and a longitudinal
slot having an opening in the distal end of the handle. A boring shaft (drill) is
coupled to the distal end of the main handle. The boring shaft includes a distal boring
tip and a pin guide proximally adjacent the boring tip for guiding the fixation pin
into the medullary canal. The pin handle is shaped and sized to slidably move within
the longitudinal slot, and may be provided with finger grips and a distal bore into
which the fixation pin is received. The fixation pin preferably includes a substantially
straight proximal and central portions, and a curved distal portion having a preferably
blunt tip. Initially, the curved distal portion rests within the pin guide of the
boring shaft. It will be appreciated that relative distal movement of the pin handle
within the slot of the main handle causes the distal portion of the fixation pin to
move through and beyond the pin guide.
[0013] In use, the main handle of certain embodiments of the instrument is manipulated to
subcutaneously introduce the boring shaft into the base of the fractured metacarpal
bone in a hand of a patient. Once the tip of the shaft has entered the base of the
metacarpal bone, it is left in position, and the pin handle is moved distally relative
to the main handle to force the distal portion of the fixation pin into the bone.
The pin thereby enters the natural hollow of the medullary canal of the bone. The
main handle is then moved proximally relative to the pin handle to remove the boring
shaft from the hand of the patient, and to disengage the main handle from the pin
handle. The pin handle is then further moved to force the pin through the natural
hollow of the medullary canal of the fractured metacarpal bone until it extends through
the canal on either side of the fracture and provides the
[0014] necessary immobilization of the fractured bone. The blunt tip prevents the pin from
piercing the distal end of the metacarpal bone. Finally, the proximal end of the pin
is bent, cut, and preferably subcutaneously seated.
[0015] According to other embodiments of the instrument of the fracture fixation system,
the instrument includes a shaft handle having at its distal end a boring shaft coupled
thereto. The boring shaft has an internal pathway and a distal exit. The shaft handle
includes a throughbore in communication with the internal pathway of the shaft and
through which the fixation pin can be received. The handle permits manual subcutaneous
insertion and rotation of the shaft to provide the tip of the boring shaft into the
metacarpal bone. The distal exit may be either axial or lateral. An awl member may
be optionally provided in the throughbore and internal pathway and extended to the
distal exit of the shaft for shaft insertion into the metacarpal bone, and then removed
for extending the fixation pin through the internal pathway and distal exit of the
shaft. According to another embodiment, the pathway of the boring shaft is provided
with a proximal lateral entrance, and exits either laterally or axially at the distal
end of the shaft.
[0016] In addition, the fixation pin may alternatively be adapted to be self-guiding to
follow the medullary canal. The proximal and central portions of the pin are relatively
straight and sufficiently stiff (providing fixation, yet permitting forced insertion
into bone). Adjacent the distal end, a reduced diameter portion is provided which
permits the distal end to easily bend relative to the central portion and follow the
medullary canal. Preferably, a coil is provided about the reduced diameter portion
to provide the pin with an apparently constant diameter.
[0017] Furthermore, the fixation pin may be particularly adapted for use in relatively small
medullary canals such as that found in the phalanges, i. e., the fixation pin may
have a relatively small distal diameter. In order to permit such a fixation pin to
be used with the same pin handle as used for fixation pins adapted for metacarpal
and metatarsal bones, the fixation pin includes a proximal end having a uniform diameter,
and a distal end having a relatively smaller diameter, and a tapered or stepped portion
therebetween.
[0018] According to yet another embodiment of the invention, the fixation system includes
a plurality of fixation pins and an instrument for sequentially implanting at least
two of the fixation pins into the medullary canal of a fractured bone. The instrument
is substantially as described above, with each of the pins separately providable into
the pin handle. The pins may have the same diameter or may be provided as a set to
include pins of various diameters. Each individual pin is smaller than the medullary
canal of the bone, yet when implanted in combination with one or more others of the
pins provides a fixation system which approximates the inner diameter of the medullary
canal in order to provide the required fixation. Each individual pin is implanted
as described above, and at least two pins are implanted to stabilize the fracture.
A collet is preferably provided over the proximal ends of the pins to couple the pins
together and thereby prevent relative rotation of the pins. In addition, the collet
is preferably adapted to be coupled to the bone to immobilize the proximal ends of
the pins relative to the bone. As such, the fixation system provides torsional stabilization
to the fracture.
[0019] In one embodiment a fracture fixation system for stabilizing a fracture of a human
bone, comprises a fixation pin having a proximal end and a distal end; and an elongate
shaft having a proximal end, a distal end with means for boring a hole in the bone,
and a pin guide adjacent said distal end of said shaft for guiding said fixation pin
into a medullary canal of the bone, said fixation pin and said shaft both adapted
such that said distal end of said fixation pin is movable beyond said distal end of
said shaft.
[0020] The first handle may be coupled to said proximal end of said fixation pin which facilitates
movement of said fixation pin relative to said shaft and through said pin guide, said
first handle preferably including a finger engageable structure which facilitates
movement of said fixation pin into the medullary canal. A second handle may be coupled
to said proximal end of said shaft to facilitate movement of said shaft into the bone,
said second handle preferably provided with a longitudinal opening into which said
first handle is received and distally slidable therein. Said second handle may be
either removable from said longitudinal opening or releasably engageable within said
longitudinal opening.
[0021] Said pin guide may be a groove in said shaft at or adjacent said distal end of said
shaft, said groove preferably including a proximal sloped surface and a distal curved
surface.
[0022] Said means for boring may include a plurality of cutting edges which meet at a point.
[0023] Said pin guide may be a distal axially exiting bore in said shaft, preferably including
a cutting edge about said exiting bore, or said pin guide is a distal laterally exiting
bore in said shaft.
[0024] At least one of said first handle and said second handle may be provided with means
for gripping with a hand of a person.
[0025] Said second handle may be provided with a throughbore, said shaft may include an
axial pathway in communication with said throughbore, and said fixation pin is axially
movable through said throughbore and said axial pathway.
[0026] Said axial pathway of said shaft may include one of an axial exit and a lateral exit
at or adjacent said distal end of said shaft.
[0027] Said shaft may include a pathway, a proximal lateral entrance into said pathway,
and a distal exit from said pathway, said fixation pin may be adapted to extend through
said lateral entrance, said pathway, and said exit.
[0028] A guide tool may have a shaft provided with a slot, said slot having a lateral opening
sized to fit over said fixation pin.
[0029] Said fixation pin may comprise an elongate rod having a proximal portion, a central
portion, and a curved distal portion.
[0030] Said proximal portion is straight and said central portion is straight and/or said
central portion is angled at an angle relative to said proximal portion where said
angle is preferably approximately 5° to 8° and said curved distal portion preferably
has a radius of curvature of approximately 0.5 inch.
[0031] Said fixation pin may be provided with a reduced diameter portion adjacent said distal
end of said fixation pin, and a coil may be preferably provided about said reduced
diameter portion.
[0032] Said pin guide may be adapted to deflect said distal end of said fixation pin at
an angle relative to a longitudinal axis of said shaft when said fixation pin is moved
distally relative to said shaft.
[0033] Said fixation pin may have a distal portion terminating in said distal end, said
distal portion having non-linear shape, and said pin guide may define a non-linear
shape substantially similar to said non-linear shape of said distal portion of said
fixation pin, such that when said boring tip of said shaft is entered into the bone
and said fixation pin may be moved distally relative to said shaft, said pin guide
guides said fixation pin into said medullary canal of the bone at an angle relative
to a longitudinal axis of said shaft.
[0034] Said non-linear shape of said distal portion of said fixation pin may include a proximal
straight first portion and a curved distal second portion.
[0035] Said pin guide may comprise a groove in said shaft, said groove including a surface
having a first portion which is angled at approximately 5° - 8° relative to said longitudinal
axis and a second portion which has a radius of curvature of approximately 0.50 inch.
[0036] Said fixation pin may be sized to fit into the medullary canal of one of a human
metacarpal bone, human metatarsal bone, human phalangeal bone, pediatric ulna bone,
and pediatric radial bone.
[0037] Said fixation pin may be sized to snugly fit within the medullary canal of the bone
and has a stiffness sufficient to immobilize the fracture and a flexibility sufficient
to permit the fixation pin to bend to facilitate insertion into the medullary canal.
[0038] At least one additional fixation pin may be provided, said fixation pins each being
sized to fit together within the medullary canal of the bone and having a combined
stiffness sufficient to immobilize the fracture and an individual flexibility sufficient
to permit each of said plurality of fixation pins to bend to facilitate insertion
into the medullary canal. A means for securing said proximal ends of said fixation
pins together may be provided.
[0039] Said means for securing additionally may secure said fixation pins to the bone. Said
means for securing may include a collet and a fastener, said collet surrounding said
proximal ends of said fixation pins, and said fastener extending through said collet
and into the bone, said collet preferably provided with self-tapping threads. Said
fixation pins may be sized to fit together within the medullary canal of one of a
human metacarpal bone, human metatarsal bone, human phalangeal bone, pediatric ulna
bone, and pediatric radial bone. Each of said plurality of fixation pins may be provided
with a distal diameter between approximately 0.035 inch - 0.060 inch.
[0040] Additional objects and advantages of the invention will become apparent to those
skilled in the art upon reference to the detailed description taken in conjunction
with the provided figures.
Figure 1 is a perspective view of a first embodiment of a fracture fixation system;
Figure 2 is a side view of the first embodiment of the fracture fixation system with
the distal end of a drill of the system shown in section;
Figure 3 is a bottom view of the first embodiment of the invention;
Figure 4 is a distal end view of the fracture fixation system of the invention;
Figure 5 is an enlarged section view of the distal end of the drill according to the
first embodiment of the fracture fixation system of the invention;
Figure 6 is an enlarged bottom view of the drill of the distal end of the drill according
to the first embodiment of the fracture fixation system of the invention;
Figure 7 is an enlarged distal end view of the drill of the according to the first
embodiment of the fracture fixation system of the invention;
Figure 8 is a cross-section through line 8-8 in Figure 7;
Figures 9, 10, and 11 are cross-section views through lines 9-9, 10-10, and 11-11,
respectively, in Figure 2;
Figure 12 is a side view of the fixation pin of the fracture fixation system of the
invention;
Figure 13 is an enlarged perspective view of the distal end of the shaft and the fixation
pin;
Figure 14 is a perspective view of the system of the first embodiment of the invention
with the pin handle and fixation pin shown in a partial distal configuration relative
to the main handle and drill;
Figure 15 is a perspective view of the system of the first embodiment of the invention
with the pin handle and fixation pin shown separated from the main handle and drill;
Figure 16 is a perspective view of a second embodiment of the fracture fixation system
according to the invention;
Figure 17 is a perspective view of a supplemental re-guiding tool for use in the fracture
fixation according to the invention;
Figure 18 is a side elevation of a second embodiment of the instrument of the fracture
fixation system of the invention shown with an inner awl component extending through
the shaft;
Figure 19 is a side elevation of the second embodiment of the instrument shown a fixation
pin extending through the shaft in place of the inner awl component;
Figure 20 is a side elevation of a third embodiment of the instrument of the fracture
fixation system of the invention;
Figure 21 is a side elevation of a fourth embodiment of the instrument of the fracture
fixation system of the invention;
Figure 22 is an alternative embodiment of the fixation pin of the of the fracture
fixation system of the invention;
Figure 23 is a perspective view of a fifth embodiment of fracture fixation system;
Figure 24 is side elevation of a set of fixation pins according to a sixth embodiment
of the invention;
Figure 25 is a section view of a torsionally stabilized fixation system according
to the sixth embodiment of the invention;
Figure 26 is a top view of a collet according to the sixth embodiment of the invention;
Figure 27 is a section view of a torsionally stabilized fixation system according
to a seventh embodiment of the invention;
Figure 28 is a top view of a first collet according to the seventh embodiment of the
invention; and
Figure 29 is a top view of a second collet according to the seventh embodiment of
the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0041] As stated above, the invention will be described with reference to a fracture in
a metacarpal bone, although it also applies to fixating fractures in metatarsal and
phalangeal bones. Turning now to Figures 1 through 4, a metacarpal fracture fixation
system 10 for the insertion of a fixation pin into the medullary canal of a fractured
metacarpal bone is shown. The system 10 includes a fixation pin 12 and an instrument
14 for implanting the fixation pin. According to a first embodiment of the invention,
the instrument 14 includes a main handle 16 provided with a stationary drill 40, and
a pin handle 18 movable relative to the main handle for implanting the fixation pin
12.
[0042] The main handle 16 includes a proximal end 20, a preferably frustoconical distal
end 22, a longitudinal drill slot 24 (seen best in Figs. 1 and 9) preferably in alignment
with a longitudinal axis A
H of the main handle 16, two radial bores 26, 28 which extend into the drill slot 24,
and a pin handle slot 30 and pin handle bore 32 (seen best in Figs. 11 and 15), both
for receiving the pin handle 18, as described below. The main handle 16 is preferably
chamfered about the pin handle slot 30, and also preferably includes a plurality of
indentations 34 to facilitate engagement of the main handle 16 by the fingers of one
hand (or both hands) of the physician. The main handle is preferably molded from plastic,
e.g., ABS, nylon, polycarbonate, or polyethylene, but may be machined from a Delrin™
rod or a similar material.
[0043] The drill 40 is provided in the longitudinal drill slot 24. The drill 40 includes
a shaft 42 having a proximal end 44 provided with two lateral bores 46, 48 (Fig. 2),
and a distal end 50 described in detail below. The drill 40 is fixed in the main handle
16 with two pins 54, 56 secured, preferably by interference fit, through the lateral
bores 26, 28 in the main handle 16 and into the lateral bores 46, 48 in the shaft
42 of the drill 40. The drill 40 is preferably made from a stainless steel bar having
a 0.125 inch diameter and a length of approximately 5.7 inches. Approximately 1.7
inches of the shaft is provided in the handle and approximately 4 inches of the shaft
extend distally from the main handle 16.
[0044] Referring to Figs. 5 through 8, the distal end 50 of the shaft 42 of the drill 40
includes a boring tip 60 which preferably comprises three cutting edges 62, 64, 66
displaced 120° from each other about the boring tip and tapered to a point 68. The
taper is preferably at approximately 13° relative to the longitudinal axis A
S. In addition, and according to a preferred aspect of the invention, the distal end
52 is provided with a lateral guiding groove 70 which guides the fixation pin 12.
The guiding groove 70 includes a proximal sloped portion 72 and a distal curved deflecting
portion 74. The sloped portion is preferably sloped such that a line L
P perpendicular to a surface 76 of the sloped portion 70 is angled approximately 5°
to 8° relative to a line L
S perpendicular to the axis A
S of the shaft 42. The curved portion 74 preferably has a radius of approximately 0.50
inches. In a preferred embodiment, the guiding groove 70 preferably extends into the
shaft 42 a groove depth D
G of approximately 0.110 inches at the intersection of the sloped portion 72 and the
curved portion 74, and preferably has a width W
G of approximately 0.063 inches. The groove depth D
G is preferably greater than the diameter of the pin 12 such that the combined diameters
of the pin 12 and the shaft 42 at the guiding groove 70 does not exceed the outer
diameter of the shaft (Fig. 13). The width W
G is preferably 0.002-0.003 inch greater than the diameter of the pin so that the pin
is accurately guided without binding.
[0045] Referring to Figs. 1-4, 9-11, and 14-15, the pin handle 18 includes a distal portion
80 which is sized and shaped to slidably move within the pin handle slot 30 of the
main handle 16, and a proximal portion 82 which is sized and shaped to slidably move
within the pin handle bore 32 of the main handle 16. A lower area 84 of the distal
portion 80 includes a plurality of indentations 86 which facilitates movement of the
pin handle 18 relative to the main handle 16 by fingers of the physician. A distal
end 88 of the pin handle 18 is chamfered and provided with a bore 90 into which the
fixation pin 12 is secured, preferably by an interference fit. The pin handle 18,
like the main handle 16, is also preferably molded from plastic, e.g., ABS, nylon,
polycarbonate, or polyethylene, but may be machined from a Delrin™ rod or a similar
material.
[0046] As shown in Figures 2 and 12, the fixation pin 12 preferably includes a substantially
straight proximal portion 92, the end of which is secured in the distal end 88 of
the pin handle 18, a substantially straight central portion 94, which may optionally
be angled relative to the proximal portion 92, and a curved, distal portion 96 having
a preferably blunt tip 98. If the proximal portion 92 and central portion 94 are angled
relative to each other, it is preferable that the angle be approximately 5°-8°. The
distal tip 96 is preferably curved about an approximately 0.50 inch radius for approximately
33° degrees. The fixation pin 12 is preferably made from a solid metal wire material,
e.g., stainless steel. It will be appreciated that the fixation pin must have a stiffness
sufficient to immobilize the bone fracture, yet be resiliently flexible enough to
permit the pin 12 to be sufficiently bent for insertion into the medullary canal of
the bone, as described below. Therefore, the system 10 may include a plurality of
fixation pins 12 having various diameters. One preferred fixation pin 12 preferably
has a length of approximately 6.0 inches, with approximately 0.70 inches secured in
the distal bore 90 of the pin handle 18, and a diameter of approximately 0.060 inches.
[0047] Referring now to Figs. 1, 13, and 14, the fixation pin 12 is positioned in the pin
handle 18, and the pin handle 18 in the main handle 16 such that the curved distal
portion 96 of the fixation pin 12 rests within the guiding groove 70 of the shaft
42 of the drill 40, and the distal portion 96 does not extend beyond the circumferential
profile of the shaft. Referring to Fig. 14, movement of the pin handle 18 within the
pin handle slot 30 and pin handle bore 32 of the main handle 16 distally relative
to the main handle causes the distal portion 96 of the fixation pin 12 to move relative
to the shaft 42 of the drill 40, through the guiding groove 70, and to extend beyond
the boring tip 60, preferably at an angle relative to the axis of the shaft A
S. The pin handle may be moved to extend the distal end of the pin preferably at least
one quarter inch, and more preferably one to three inches, beyond the distal end of
the shaft while remaining coupled to the main handle. Moreover, it will be appreciated
that no impediment is present which inhibits the pin handle 18 from being moved distally
relative to the main handle 16, or the main handle moved proximally relative to the
pin handle. As such, as shown in Fig. 15, the pin handle may be separated from the
main handle.
[0048] In use, the main handle 16 of the instrument 14 is manipulated by hand to subcutaneously
introduce the boring tip 60 of the drill 40 into the base of a fractured metacarpal
bone. Once the boring tip 60 of the drill 40 has entered the base of the metacarpal
bone, the drill is oriented such that the guiding groove 70 is oriented to guide the
fixation pin 12 through the natural hollow of the medullary canal of the metacarpal
bone. The pin handle 18 is then manually moved relative to the main handle 16 to force
the curved distal portion 96 of the fixation pin 12 into the bone. The main handle
16 is then moved proximally relative to the pin handle 18 to remove the drill 40 from
the bone and disengage the main handle from the pin handle. This is performed while
preferably maintaining the pin handle, and the fixation pin which is attached thereto,
at its present location. The pin handle is then manipulated to move the pin through
the canal of the fractured metacarpal bone until the pin extends on either side of
the fracture and provides the necessary immobilization of the fractured bone. It will
be appreciated that the complementary shape of the fixation pin and groove (e.g.,
the 5°-8° angle of the central portion of the pin relative to the proximal portion
of the pin is substantially similar to the 5°-8° angle of the proximal portion of
the groove, and the 0.50 inch radius of curvature of the distal portion of the pin
is substantially the same as the 0.50 inch radius of curvature of the distal portion
of the groove), facilitates directing the fixation pin into the medullary canal. The
blunt tip 98 of the fixation pin 12 prevents the pin from piercing the distal end
of the metacarpal bone. Finally, once the physician determines that the fixation pin
is properly fixating the fractured bone, the pin handle 18 may then be manipulated
to bend the fixation pin 12 adjacent the cutaneous entrance hole, the pin is cut,
and the cut end is either subcutaneously seated or covered with a bandage outside
the skin. After fracture healing, the fixation pin is extracted, e.g., with pliers,
from the bone and then discarded. The cutaneous entrance hole is then permitted to
heal.
[0049] It will be appreciated that the fracture fixation system of the invention provides
substantial fixation to a metacarpal fracture, yet does not require an unduly invasive
procedure or a large number of steps. In addition, the procedure reduces the number
of physician "hands", relative to invasive surgery, required to sufficiently immobilize
a fracture for proper healing.
[0050] Turning now to Fig. 16, a second embodiment of an instrument 214 for a fracture fixation
system 210, substantially similar to the first embodiment (with like parts having
numbers incremented by 200) is shown. The instrument 214 includes a shaft 240 having
a distal guiding groove 270 and sharp boring end 260. The shaft 240 includes a shaft
handle 216 for manipulating the shaft. The shaft handle 216 includes a slot 230 into
which a pin handle 218 is slidably received. The slot 230 preferably slopes downward
toward the shaft. The shaft handle 216 is further provided with grips 217 for stably
gripping the shaft handle 216 in a hand of the physician. The pin handle 218 includes
a ridge 219 which may be used to leverage relative distal movement of the pin handle
through the slot 230 of the shaft handle 216. The pin handle 218 and the shaft handle
216 are preferably positively engagable relative to each other, e.g., with a snap
fit, and may be disengaged by sufficient force on the ridge 219 of the pin handle
to move the pin handle relative to the shaft handle. Release may also provide tactile
indication that the handles have disengaged and a tip 298 of the pin 212 has moved
slightly ahead of the boring tip 260 of the shaft 240. The slope of the slot 230 permits
a fixation pin 212 provided axial within the pin handle to be directed toward and
through the guiding groove 270 when the pin handle is located in the slot 230 and
moved within the slot. The pin 212 is preferably angled relative to a longitudinal
axis A
P of the shaft handle 216 such that the pin 212 is directed toward the shaft 240. Preferably,
the fixation pin 212 includes a proximal portion 292 and a central portion 294 which
are coaxially aligned, and a distal portion 296 provided with the blunt, preferably
curved tip 298. In operation, after the boring end 260 of the shaft 240 has been inserted
into the metacarpal bone, the pin handle 218 is moved distally relative to the shaft
handle to move the pin 212 through the guiding groove 270 and into the medullary canal
of the fractured bone. The shaft handle 216 is then removed from the pin handle 218,
and the pin handle is manipulated to further extend the fixation pin through the medullary
canal of the bone and fixate the bone. After the physician is assured that the fixation
pin provides desirable fixation of the fracture (i.e., that it has sufficient diametric
fit within the medullary canal), the pin is bent and cut at the skin surface.
[0051] It will be appreciated that after inserting a fixation pin into the medullary canal
(but prior to bending and cutting the pin), in certain circumstances, the physician
may determine that the inserted pin is unsuitably sized for the particular patient,
and that a fixation pin having a different diameter is required. To that end, a set
of fixation pins including fixation pins having distal portions of various sizes (e.g.,
substantially 0.060, substantially 0.051 inch, substantially 0.045 inch, substantially
0.038 inch, and substantially 0.035 inch) is provided for use by the physician. However,
if the pin presently inserted in the hand is removed from the hand for replacement,
the entry hole in the bone will be difficult to relocate. Therefore, referring to
Fig. 17, a supplemental re-guiding tool 300 may be provided in the system of the invention.
The re-guiding tool 300 includes a handle 302, a slotted shaft 304 extending from
one end 306 of the handle and having an inclined leading edge 308, and a tubular bending
portion 310 extending from the other end 312 of the handle. The handle 302 is preferably
further provided with a depression 314 into which the thumb of the physician may seat
and which thereby facilitates gripping the handle.
[0052] The slotted shaft 304 of the re-guiding tool 300 may be extended over the fixation
pin which the physician wants to replace, through the entry hole in the hand, and
into the hole in the bone. The inclined leading edge 308 facilitates insertion of
the shaft through the wound of the hand with minimal trauma to the area. It will be
appreciated that the slotted shaft design provides a less traumatic manner of maintaining
a pathway from the entry hole in the skin to the bone than reinserting the distal
end of the boring shaft (drill). The fixation pin may then be removed, while the slotted
shaft 304 acts as a guide for the replacement pin. Once the proper fixation pin has
finally been determined, the pin is cut and the re-guiding tool 300 may be reversed
and the bending portion 310 may be extended over the cut pin and used to leverage
the bending of the pin for subsequent subcutaneous seating. While the guide tool 300
is most appropriately used with the first and second embodiments of the invention
(which are provided with lateral pin guides), it will be appreciated that the guide
tool may also be used with any of the following embodiments.
[0053] Turning now to Fig. 18, a third embodiment of an instrument 414 for a fracture fixation
system 410 according to the invention is shown. The instrument 414 includes a shaft
handle 416 having an axial throughbore 424 and a boring shaft 440 coupled in the distal
end thereof. The shaft 440 is cannulated; i.e., the shaft 440 is provided with an
internal pathway 470, and preferably includes a distal tip 460 with an axial pathway
exit 471 and a preferably sharp annular cutting edge 473. The axial throughbore 424
and internal pathway 470 are in communication with each other and preferably axially
aligned. A rod-like awl 419, provided with a proximal handle 421, is extendable through
and removable from the pathway 470. The awl 419 preferably has a length such that
when the handle 421 of the awl is seated flushly against the shaft handle 416, the
tip 423 of the awl extends through the pathway exit 471 and operates as a boring tip.
The inner awl and shaft may be locked together for insertion into the bone. The awl
is then unlocked and removed from the internal pathway 470 to permit a fixation pin
412 to be fed through the pathway 470 and out the pathway exit 471 (Fig. 19).
[0054] In use, the awl handle 421 and shaft handle 416 is used to insert the tip 423 of
the awl 419 and the tip 460 of the shaft 440 into the metacarpal bone. The awl handle
421 is then removed from the pathway 470, and the fixation pin 412 is maneuvered through
the pathway and into the medullary canal. Once the fixation pin is sufficiently extended
in the medullary canal to fixate the bone on either side of the fracture, the main
handle 416 is proximally removed from over the pin 412. The pin may then be further
manipulated, and is finally cut at the desired length.
[0055] Referring now to Fig. 20, a fourth embodiment of an instrument 514 for a fracture
fixation system 510 is shown. The instrument 514 includes a main handle 516 having
a throughbore 524 and a boring shaft 540 coupled in the distal end thereof. The boring
shaft 540 is cannulated and, at its distal end 550 includes a sharp boring distal
tip 560 and a lateral pathway exit 571. A rod (not shown, but similar to the awl described
with respect to the second embodiment) may be provided within the pathway 570 such
that it closes the pathway exit 571 and thereby facilitates insertion of the shaft
540 into the bone. The rod, if provided, is then removed. A fixation pin 512 is then
extended through the pathway 570 and into the medullary canal of the metacarpal bones.
[0056] Turning now to Fig. 21, a fifth embodiment of an instrument 314 for a fracture fixation
system 610 is shown. The instrument 614 includes a cannulated boring shaft 640 preferably
provided with a proximal shaft handle 616, and a fixation pin 612 optionally having
a pin handle 618 coupled to its proximal end. The cannulated shaft 640 includes a
proximal lateral pin entry 669 into an axial pathway 670 of the shaft 640, and a distal
lateral pathway exit 671 oriented to guide the pin into the medullary canal. Optionally,
the pathway exit 671 may be axially aligned with the pathway 670 for axial guidance
of the pin. After the shaft 640 has been inserted into the metacarpal bone, the pin
612 manipulated through the shaft 640 and into the canal of the fractured bone to
fixate the bone. Where no pin handle is provided, the shaft 640 and shaft handle 616
are then proximally withdrawn over the pin 612, and the pin is manipulated such that
it is sufficiently inserted, bent, and finally cut to the desired length. Where the
optional pin handle 618 is utilized, the shaft 640 is moved proximally over the pin
612 toward the pin handle 618 such that the pin may be further manipulated and cut
to the desired length.
[0057] Turning now to Fig. 22, the fixation pin used in each of the above embodiments may
be alternatively configured. For example, the fixation pin 712 may be provided with
a narrowed portion 722 (i.e., a reduced diameter) adjacent the tip 720 about which
a coil 724 is preferably positioned. This configuration is provided to permit the
distal end 718 of the fixation pin to more easily bend and permit the fixation pin
to preferably be self-guiding to follow the medullary canal. In addition, as an alternative
to stainless steel, the pin 712 may be made from titanium, or another structurally
supportive biocompatible material.
[0058] Referring now to Fig. 23, the pin handle 818 of the fixation system 810 may be provided
with a set of fixation pins, substantially as described above with respect to the
first embodiment but having a variety of distal dimensions. For example, it may be
desirable to insert a pin 812 into a phalangeal medullary canal having a relatively
smaller distal diameter than would be desirable for a metacarpal bone. However, in
order to permit the pin handle 818 to easily accommodate and stably hold pins having
a variety of distal dimensions, the dimensions of the proximal portion 892 of the
pins may be provided with a preferably uniform dimension. As such, some fixation pins
812 may have a distally tapered portion 813 (or alternatively a step 813a, shown in
dotted line), along the proximal portion 892 of the pin to taper to their respective
distal dimension.
[0059] Turning now to Fig. 24, a fixation system may be provided with a plurality, or set
900, of fixation pins 912a, 912b, 912c, having the same or different relative sizes.
Each individual pin is smaller than the medullary canal of the bone, yet when implanted
in combination with one or more others of the set provides a fixation system which
approximates the inner diameter of the medullary canal in order to provide the required
fixation. Referring to Fig. 25, the pins are individually inserted into the medullary
canal of the fractured bone substantially as described above; i.e., using an instrument
including a shaft having a guiding groove and provided with a shaft handle for manipulating
the shaft, and a pin handle coupled to the proximal end of the pin. A first pin 912a
is provided in the pin handle and inserted into the medullary canal 913 of a bone
915 to extend across a fracture 911 in the bone, as described above. A second pin
912b is inserted alongside the first pin 912a, and optionally additional pins, e.g.,
912c, are likewise inserted. The distal ends of the pins may diverge to rest or imbed
in different portions of the bone, as shown or, alternatively, may remain substantially
aligned. Referring to Figs. 25 and 26, a cylindrical collet 917 is then positioned
over the exposed proximal ends of the pins to constrain the pins together such that
the pins are substantially prevented from relative axial rotation. The collet 917
preferably includes a central opening 919 adapted to stably secure the pins. For example,
for three pins, the central opening 919 may be circular with a diameter adapted to
hold the three pins together. In addition, the collet 917 also preferably includes
a means for securing the collet, and therefore the proximal ends of the fixation pins,
to the fractured bone, e.g., external and preferably self-tapping threads 921. An
external flange 923 adapted to assist in seating the collet at the desired depth in
the bone is also preferably provided. As such, the fixation system provides torsional
stabilization to the fracture.
[0060] Turning now to Figs. 27 and 28, in another torsionally stabilized fracture fixation
system, two pins 1012a, 1012b are inserted into the bone 1015 to bridge the fracture
1011 as described above. A collet 1017 having three openings 1019a, 1019b, 1019c (or
a collet 1117 having a single clover-shaped opening 1119, as shown in Fig. 29) is
provided over the proximal ends of the pins with the pins extending through two of
the openings 1019a, 1019b. In the remaining opening 1019c, a nail 1121 is provided
and secured into the bone to immobilize the collet 1017 relative to the bone.
[0061] There have been described and illustrated herein several embodiments of a fracture
fixation system. While particular embodiments of the invention have been described,
it is not intended that the invention be limited thereto, as it is intended that the
invention be as broad in scope as the art will allow and that the specification be
read likewise. Thus, while some embodiments of the fixation system have been particularly
disclosed for the fixation of fractured metacarpal bones, it will be appreciated that
the system may be used to fixate bones of similar or smaller size and for which similar
problems exist with respect to fracture fixation, e.g., metatarsal bones in the foot
and the phalanges of the fingers and toes. In addition, pediatric arm bones, e.g.,
ulna and radial bones, can be similarly treated. Therefore, the teaching here is for
the use of the system of the invention with the like bones. In addition, while particular
materials have been disclosed with respect to the various components of the system
of the invention, it will be appreciated that other suitable materials may be used
as well. For example, while a metal fixation pin has been described, less preferred
alternative materials for the fixation pin are nonmetals, in particular, bioabsorbable
materials. Furthermore, while particular dimensions and angles have been disclosed
and provide superior results, it will be understood that the components may be sized
to other suitable dimensions and angles, as long as they are adapted to be used in
a system to immobilize metacarpal bones and the like. For example, while the distal
portion of the fixation pin and the distal surface of the groove are both preferable
angled at between 5°-8°, it will be appreciated that other suitable angles, e.g.,
between 3° and 15°, may also be used. Also, while indentations are disclosed as finger
gripping means, other finger gripping means, e.g., knurls, ridges, grooves, and nubs,
may additionally or alternatively be used. In addition, while the bone boring shaft
component is described as a drill in the first embodiment, it will be appreciated
that the shaft component is not required to have any cutting edges, and may be provided
with a sharp point to enter the bone. Furthermore, while machined handles are disclosed
for moving the fixation pin relative to the shaft component, it will be appreciated
that pliers or the like may similarly be used to hold and move the pin through the
guiding means of the shaft. Further yet, while pins have been described for holding
the drill shaft in the main handle, it will be appreciated that other means for fixing
the drill in the handle. In addition, while a cylindrical collet has been shown holding
the proximal ends of pins together, it will be appreciated that devices having different
shapes and configurations can likewise be used to constrain the pin ends together.
For example, sleeves, bands, clips, staples, etc., may be used. Also, while in one
embodiment a nail is shown extending through the collet, it will be appreciated that
a screw or similar fastener can likewise be used. It will therefore be appreciated
by those skilled in the art that yet other modifications could be made to the provided
invention without deviating from its spirit and scope as so claimed.